Method and device for extracting fumes and heat and for providing operational for traffic structures and enclosed traffic spaces

ABSTRACT

The invention relates to a method and a device for extracting fumes and heat and for providing operational ventilation for traffic structures and enclosed traffic spaces. The inventive system for drawing off fumes and heat and for providing operational ventilation for traffic structures and enclosed traffic spaces does not use any pipe ventilators for extracting the fumes and builds up a vacuum throughout a duct in order to extract the fumes. The system is characterized in that a number of reversible jet ventilators are provided inside a modular smoke extraction duct situated preferably beneath the tunnel ceiling or the ceiling of an enclosed space. The jet ventilators are evenly distributed over the length of the duct and the duct itself has evenly distributed openings. The jet ventilators are able to rapidly accelerate the air or the fumes of a fire on the road in a particular direction in the duct by virtue of an impulse effect.

The invention relates to a method and a device for extracting fumes andheat in the event of a fire by the locally selective exhaustion offumes, as well as the ventilation in event of “heavy traffic” or “poorair quality” by the exhaustion of pollutant-laden air or by theselective supply of fresh air for traffic structures and spaces.

In case of fires in traffic spaces, such as tunnels, it must be ensuredthat, for a certain period of time, the visibility does not deterioratedue to the fumes and plume gases evolved to such an extent, that theintended flight paths can no longer be recognized reliably or utilizedsafely and, because of high temperatures, poisonous gases and adetonation of incompletely combusted gases, people in the traffic space,the safety facilities or the structure itself are endangered.

The previously used fume-extraction facilities in traffic structures andenclosed spaces (see EP 0428 108 A2) basically have the advantage that,on the one hand, the visibility necessary for rescuing persons andobjects is improved and, on the other, the temperatures aresignificantly lower and the amounts of fumes significantly less in thevicinity of the fire than in the absence of fume-extraction facilities.

For enclosed spaces, the fume-extraction facilities of DIN 18 232 (part1 to part 3) can be projected in such a manner, that free visibility upto a certain height is ensured for an assumed fire load. In general, forvarious reasons, this procedure is not possible for traffic structures.

For traffic structures, such as tunnels, different concepts are knownfor meeting the fire protection requirements and adhering to visibilityconditions. Essentially, there are two different methods.

In the event of a fire in a tunnel, a vigorous longitudinal ventilation,for example, over large jet ventilators, is produced in such a mannerthat the windward side of the fire is kept free of smoke in every case(no back-layering of the fumes). The axial flow velocities in thetunnel, required for this purpose, are known and range from 4 to 6 m/s.However, at these flow velocities, the lee side of the fire is filledcompletely with smoke and can no longer be used as a flight path.

The second method comprises the extraction of fumes over specialfume-extraction ducts, which are disposed over the whole length of thetunnel. Either fumes are extracted uniformly over all existing openingsin the fume-extraction duct (multi-point system) or, of the fire covers,which are distributed uniformly in the whole of the smoke-extractionduct, only those in the vicinity of the fire are opened. Over thelatter, the fire gases can then be extracted (single-point system). Thesingle-point extraction has generally turned out to be the moreefficient method.

In all known cases of fume-extraction facilities, pipe ventilators(portal ventilators) are used to extract fumes and are generally mountedcentrally to the outlet of the fume-extraction ducts, (portal orchimney) (for example, EP 0428 105 A2). These facilities can partly alsobe used for the operational ventilation, either by extractingpollutant-laden air (semi-transverse ventilation by outgoing air) or bysupplying fresh air (semi-transverse ventilation by incoming air), inthat the portal ventilators are reversed.

The essential disadvantage of all known arrangements for extractingfumes is the following. On the one hand, a reduced pressure must bebuilt up, to begin with, by the portal ventilator (pipe ventilator),which is at the end of the extraction system, so that the fire gases canbe extracted through the openings (fire covers) into the fume-extractionduct. The greatest pressure difference exists directly at the pipeventilator and the least pressure difference exists at the opening,through which the fumes are to be extracted. In the case of longerdistances, such as in tunnels, the time required to build up thenecessary reduced pressure can amount to a few minutes. On the otherhand, in the case of a single-point system, it must be assumed that allfire covers of the whole of the fume-extraction duct, which are not inthe vicinity of the fire, are pressure-tight. In the event of leakagesor if fire covers have been opened wrongly, the effectiveness of thepipe ventilator and, with that, the extraction performance are reduced.This can lead to a total failure of the system in the event of a fire.Furthermore, components and facilities, in the vicinity of the fire,including the extraction duct and the portal valves can themselves beinvolved as a result of the high temperatures of the fire. In the caseof fires in the vicinity of the portal ventilators, the latter are nolonger capable of functioning because of the high temperatures at thepipe ventilators. Moreover, two portal ventilators are generally used,resulting in twice the installed performance, in order to increase thesafety (redundancy) of the system.

If some of the fumes extracted are combusted incompletely and mixed at ahigh temperature with fresh air in the fume-extraction duct, there maybe detonations, which destroy the fume-extraction system and, inaddition, endanger persons in the traffic space.

Installations or facilities, in which the conventional fume-extractionequipment is supplemented by sprinkler equipment in the vicinity of thefire, are also known (EP 0703807 A1).

It is therefore an object of the invention to construct a fume and heatextraction device as well as operational ventilation for trafficstructures and enclosed spaces, which act essentially without delay whenswitched on, do not become ineffective due to leakages at the fume duct,offer the parts of the device themselves (fume-extraction duct andtunnel wall) reliable protection even at high fire loads and extractionof incompletely combusted gases and realize the function of operationalventilation as semi-transverse ventilation by outgoing air, assemi-transverse ventilation by incoming air and as their combination.

Pursuant to the invention, this objective is accomplished by thedistinguishing features of claims 1 and 6. Advantageous developmentsarise out of the dependent claims. In the following, the invention isdescribed by means of examples illustrated in FIGS. 1 and 2a, b and c.

The inventive method and the device of a fume and heat extractioninstallation as well as an operational ventilation for trafficstructures and enclosed spaces is characterized in that, in the interiorof a fume-extraction duct 2, constructed in modular fashion preferablybelow the tunnel ceiling 1 or the room ceiling and having large ceilingopenings 2 a, which are distributed uniformly, there is a plurality ofreversible jet ventilators 3, which are distributed uniformly over thewhole length and accelerate the air or fumes 4 of a fire 5 on theroadway 8 in the fume-extraction duct within a short time by their pulseaction 3 a in the respective direction (FIG. 1). The hot fumes, thenflowing in in the event of a fire, are cooled immediately in thefume-extraction duct indirectly by water cooling of the wallssurrounding the fume-extraction duct and/or directly by evaporativecooling 6 (jet lance and optionally “water quenching”), so that thetemperature and, in some cases, also the volume of the fumes to bedischarged are decreased and the action of the jet ventilators isintensified due to the change in the density of the fumes. Thetemperature of the fumes is adjusted by the evaporative cooling so that,even in the case of continuous operation, damage to the structure andthe installation cannot develop and hot water cannot drip into thetraffic space. The wall cooling of the fume-extraction duct and theevaporative cooling in the fume-extraction duct accordingly also resultin the protection of the structure itself.

Due to the uniform arrangement of the jet ventilators, the whole of thefume/air “column” 4 in the fume-extraction duct is quickly acceleratedat the same time in the respective direction (FIG. 1). The number andoutput of the jet ventilators 3 depend on the cross section of thefume-extraction duct 2 and on the projected extraction performance ofthe installation (amount of fumes), which can be derived from the fireload, which is to be mastered.

The extraction by the single-point system is achieved by the reversiblejet ventilators in such a manner that all jet ventilators to the rightof the fire go into operation towards the right and those to the left ofthe fire go into operations towards the left. This results in a locallylimited extraction of the fumes in the region of the fire (see also FIG.1). In the region of the fire itself the jet ventilators are notswitched on; the temperature of the fumes is lowered here, above all, byevaporative cooling.

In contrast to all known systems, the greatest reduced pressure and,with that, the greatest extraction performance in this system is at theplace, where the fumes enter the fume-extraction duct; the reduction inpressure decreases uniformly over the respective numbers of jetventilators up to the end of the fume-extraction duct. As a result, thesystem performance drops only insignificantly even if one or more of thejet ventilators fails. With that, this method and the device for theextraction of fumes and heat as well as for the operational ventilationin traffic structures and enclosed spaces differs basically from allthose previously known.

The entry of fumes and plume gases in the region of the openings of thefume-extraction duct is supported by the hot air currents of the fireitself Since static pressures are inversely proportional to velocities,a reduced pressure acts permanently in the direction of thefume-extraction duct. This ensures that all stray fumes are picked upand that fumes cannot return to the traffic space, even if there areleaks in the duct.

In the openings of the fume-extraction duct 2 a, there are either fixedair baffle plates 7 (lamellas), preferably set at an angle of 60° or 90°to the direction of flow or, in several places, controllable air baffleplates 7, with which the openings can also be closed off 2 b. Because ofthe differences in the flow velocities of the gases in the traffic space(such as a tunnel) and in the fume-extraction duct (dynamic pressurecomponents), flow of fumes from the fume-extraction duct back into thetraffic space is prevented. If extraction is to take place or can takeplace only in one direction in the smoke-extraction duct, only the jetventilators of one side need be switched on, in order to achieve thesingle-point extraction of the fumes.

For the operational ventilation according to the principle of thesemi-transverse ventilation by the outgoing air, the jet ventilators(rpm-controlled) can be operated as in the case of a fire. The jetventilators 3 to the right of the extraction opening 2 a work to theright, those to the left work to the left. If the operationalventilation is to work according to the principle of the semi-transverseventilation by incoming air, the jet ventilators 3 to the right of theextraction opening 2 a work to the left and those to the left work tothe right. For energetic reasons, however, it is sufficient for theoperational ventilation to control only one direction, the incoming airor the outgoing air, with jet ventilators of FIGS. 2a and 2 b. For thesemi transverse ventilation by incoming air, all jet ventilators to theright of the ventilation point are switched on to the left and only onejet ventilator on the left side works to the right. By these means, itis insured that the fresh air 9 at the ventilation point enters thetraffic space from the smoke-extraction duct 2. The outgoing air 10flows through the traffic space and the fume-extraction duct. For thesemi-transverse ventilation by the outgoing air of FIG. 2b, only the jetventilators 3, which lie to the left opening-ventilation point 2 a areswitched on towards the left; this results in a single-point extractionof the outgoing air. The fresh air 9 is supplied over the traffic spaceand the fume-extraction duct 2 with appropriately set air baffle platesin the openings 2 a. The combination of semi-transverse ventilation byoutgoing air and semi-transverse ventilation by incoming air of FIG. 2cis also possible for an operational ventilation.

Above all, the advantages achieved with the invention lie therein that

the system reacts rapidly in the event of a fire (high extractionperformance in the single-point system independently of the position ofthe fire),

leakages have no effect on the extraction performance because of thefunctioning principal,

there is no damage (even if the installation works for a longer time)because the fumes are cooled directly and/or indirectly

there can be no detonations,

by appropriately controlling the jet ventilators, the device realizes asemi-transverse ventilation by outgoing air as well as a semi-transverseventilation by incoming air and

the system performance is decreased only insignificantly by the possiblefailure of some jet ventilators.

The method and device for extracting fumes and heat and for providingoperational ventilation for traffic structures and enclosed spaces ofclaims 1 to 10 can advantageous can be combined with the alreadyproposed Method For Purifying Outgoing Air By Removing Particles AndGases of DE 196 46 766.7.

The contents of the Figures are summarized once again in the following.

FIG. 1 diagrammatically represents the case of a fire in the tunnel withextractions of fumes and heat on both sides. In the region of thedetected fire 5, the jet ventilators 3 remain switched off; evaporativecooling 6 is switched on here. To the right and left of the fire 5, upto the end of the fume-extraction duct, all jet ventilators 3 areswitched on and the ceiling openings are closed off preferably overcontrollable air baffle plates 7. Consequently, a single pointextraction results in the region of the fire 5.

FIGS. 2a, 2 b and 2 c represent the operational state of ventilationwith the functions of semi-transverse ventilation by incoming air and byoutgoing air and the combination of these two types of ventilation.

What is claimed is:
 1. A method for the extraction of gases and heat inthe event of a fire as well as for operational ventilation in trafficstructures and traffic enclosed spaces having a ceiling by means of aceiling duct having openings which are adjustable to be open or closedoff downward towards the traffic space and reversible jet ventilators inthe duct of controllable rpm and capable of being pulsed, wherein, inthe case of a fire, gases in a length of the ceiling duct commencingfrom a location of the fire and extending up to an end of the duct areaccelerated uniformly over said length by pulsing of the jet ventilatorsin such a manner that the greatest reduced pressure or the highestextraction performance is produced at those of said openings which arein the vicinity of the fire, where the jet ventilators are not inoperation, and a single-point extraction takes place, said extractionbeing so effected as to be two-sided or in one direction by socontrolling the reversible jet ventilators as to attain either saidtwo-sided extraction or said extraction in one direction and in the caseof ventilation, operational ventilation with the functions ofsemi-transverse outgoing air ventilation, semi-transverse incoming airventilation or a combination of semi-transverse incoming air ventilationand semi-transverse outgoing air ventilation is effected by so operatingthe reversible jet ventilators as to effect a selected one of saidfunctions.
 2. The method of claim 1, wherein the gases in the ceilingduct are accelerated in such a manner in the event of a fire thatvelocity of the gases in the ceiling duct is higher than that in thetraffic space, whereby a permanent, dynamic reduced pressure is producedby the Bernoulli principle thereby to effect a flow of the gases in thedirection of the ceiling duct.
 3. The method of claim 1, furthercomprising cooling the duct and apparatus associated therewith by meansof water in the event of fire.
 4. The method of claim 1, wherein, in theevent of fire, hot gases, after entering the openings, are cooled byevaporative cooling means, which are disposed in the interior of theceiling duct and distributed over the whole length of the ceiling duct,and the final cooling temperature is controlled so that no condensate isformed.
 5. Apparatus for the extraction of gases and heat in the eventof fire as well as for operational ventilation in traffic structures andtraffic enclosed spaces having a ceiling, comprising a ceiling ducthaving openings communicating with the interior of the traffic structureor traffic endorsed space, reversible jet ventilators in the duct ofcontrollable rpm and capable of being pulsed, said jet ventilators beingdistributed over the entire length of the duct, wherein, in the case ofa fire, gases in a length of the ceiling duct commencing from a locationof the fire and extending up to an end of the duct are accelerateduniformly over said length by pulsing of the jet ventilators in such amanner that the greatest reduced pressure or the highest extractionperformance is produced at those of said openings which are in thevicinity of the fire, where the jet ventilators are not in operation,and a single-point extraction takes place, said extraction being soeffected as to be two-sided or in one direction by so controlling thereversible jet ventilators as to attain either said two-sided extractionor said extraction in one direction and in the case of ventilation,operational ventilation with the functions of semi-transverse outgoingair ventilation, semi-transverse incoming air ventilation or acombination of semi-transverse incoming air ventilation andsemi-transverse outgoing air ventilation is effected by so operating thereversible jet ventilators as to effect a selected one of saidfunctions.
 6. Apparatus according to claim 5, further comprising waterejecting means disposed in the duct.
 7. Apparatus according to claim 5,further comprising baffle plates in the openings.
 8. Apparatus accordingto claim 5, further comprising louvers in the openings and means forcontrolling the louvers.
 9. Apparatus according to claim 5 wherein theduct containing jet ventilators is comprised of a plurality of modules,each of said modules comprising a predetermined length of ductcontaining a predetermined number of jet ventilators.